Kiwifruit Propagation

Arlie A. Powell

Horticulturist-Fruits, Auburn University

June, 1998

Kiwifruit propagation is most easily achieved using softwood cuttings
taken in June and July and possibly August. Budding of seedling plants
also works fine, but this method is not recommended because of freeze problems.

Make 2-to 3- node cuttings (2 to 3 leaves) from mature, current season
shoots (usually 3 to 6 inches long). The leaves should be full size and
buds evident at base of leaf petiole. Less mature wood such as the ends
of shoots will not work.

In preparing cuttings, cut just below the lowest bud on each stem piece
and remove all leaves but the upper one. The blade portion of the remaining
leaf should be cut in half (removing the outer half). The top part of the
cutting should be trimmed such that only 1/2 inch or less of stem projects
beyond point of attachment of remaining leaf.

Trim away the bark tissue (with a knife) on two sides of the lower part
of the cutting (stem base) for a distance of 1/2 to 3/4 inch. This cutting
action should just barely slice into both sides of the basal bud. This
is referred to as wounding.

The bottom half of cuttings should be immersed in a plant hormone solution
for five seconds and then placed into a rooting bed or small pots for 60
days or more. During this initial period of callous and root development,
cuttings should be in a greenhouse (or shadehouse) that only allows about
50% light penetration. Shade cloth etc., can be used on greenhouses if
necessary. Cuttings must be maintained under intermittent mist (usually
5 seconds of mist every 5 minutes during daylight hours). If soil (or any
media that may be contaminated with soil borne fungi) is used in the rooting
bed, all the media should be sterilized before use.

Rooting hormones can be purchased from any number of horticultural supply
houses and some farm supply stores. Work done in South Carolina indicates
a concentration of 6000 ppm of indole - 3- butryic acid (IBA) works better
than other hormone treatments. However, some of the commercial brand products
on the market usually contain naphthaleneacetic acid (NAA) or indole acetic
acid (IAA) along with IBA. Although not ideal, these products usually suffice
for kiwi propagation on a small scale. Liquid solutions are best for dipping
cuttings but powdered forms of commercial products are fine for doing small
numbers of cuttings.

One of the most damaging problems growers in Alabama have experienced
in rooting and growing kiwifruit plants is dieback of young cuttings (or
plants) in the nursery. This is generally caused by soil borne fungi. Sterilization
of rooting media helps but additional treatments with fungicides may be
needed.

Once cuttings have developed some roots and initiated shoot development,
they should be transferred into gallon size pots for further development
into three- to five-foot plants ready for field planting. Five- to six-foot
bamboo stakes will be needed for each container for growing straight trunk
plants. As plants continue growing in the summer months the terminal of
each shoot must be pinched when it begins to wind around itself. A new
shoot must be selected near the point where the terminal was cut and all
others removed. Allow this shoot to grow upward and continue tying to bamboo
stake to form a straight trunk (don't allow stem to wrap around the bamboo).
Continue to pinch the terminal when it winds around itself and repeat the
training process.

When rooted cuttings are placed in gallon size containers it is usually
best to apply a slow release fertilizer (such as osmocote or equivalent)
at recommended rates usually two times during the growing season (March
and July are best). Generally 1 teaspoon of slow release fertilizer per
gallon pot is adequate. Most of the slow release fertilizers being used
have analyses such as 18-6-12, 17-7-12 or others with similar ratios.

Kiwifruit plants have a high water requirement. Plants grown in gallon
sized pots should be watered at least daily, depending upon potting media
used.

When growing plants in gallon containers there are several options the
grower has regarding potting media. Standard premix nursery potting media
usually works fine. Mixes which some nurseries have used in past years
such as 1/3 peat, 1/3 soil and 1/3 sand or perlite are quite satisfactory.
If soil is used in the mix (or any other component which may be contaminated
with soil borne fungi), sterilization of the media is recommended before
potting rooted cuttings.

Recently nurseries have begun using less costly potting media such as
pine bark for growing many plant types. This works fine for kiwifruit also.
The addition of a small amount of peat moss improves the mix and is recommended.
Usually 4 or 5 parts bark and 1 part peat is satisfactory. Kiwifruit tolerate
low pH, but lime should be added to the mix (6 to 10 lbs of agricultural
lime per cubic foot of mix is usually adequte) to attain a pH of 6 to 6.5.
A starter fertilizer such as Pro Start II (or equivalent) should be added
at a rate of 6 lbs per cubic yard of mix.

Apply pesticides on an as needed basis. A spray of Benlate plus Captan
has worked well on controlling a disease of mature leaves (thought to be
alternaria) that usually becomes evident in June and July. Some 2 to 4
sprays may be needed at 10 to 14 day intervals. A rate of 1/2 lb of Benlate
50W plus 2 lbs Captan 50W per 100 gallons of water (for dilute spray) works
well.

Brand names used in this publication are for clarity only. The mention
of a brand name in no way constitutes endorsement of this brand or product
by the Cooperative Extension Service. Nor is there intended any discrimination
against similar unnamed products or brands which may be just as effective.